What are the production differences between the
original Drake TR-7 Transceiver and the later production of the TR-7A?Between the TR-7 and the TR-7A there were basically five circuit changes. Along with the
circuit changes the only physical differences were the front panel (see page two for details) and the labeling of
a rear panel connector. The circuit changes include:

A 500Hz filter (SL-500) has been installed in selectivity position "A"

Selectivity "B" has been adapted to provide a bandwidth of 9kHz for AM reception.

A surge protection device has been added to the receive antenna input to provide additional protection from
static discharges from lightning.

The unused phono style tip-jack on
the rear panel has been labeled "TX", and now provides an alternate audio input to the transmitter for
sources other than microphone.This jack is connected in parallel
with pin 1 on the front panel microphone jack.
See below the pictures showing the connector labeling on the TR-7A
rear panel.

Here again you need to be cautious if you suspect a TR-7 identity
issue. Someone could easily use black
rub-on lettering for the transmit audio connector creating a look-alike TR-7A rear panel.

Other Noteworthy Items:

Here are a few other bits of information I uncovered during
my research. Drake no longer has any records of how many TR-7 transceivers were manufactured. The best we
can determine Drake built around 10,500 TR-7's and around 2500 TR-7A's. We know the TR-7A
production started with a serial numbering around the high 10,800's range, and the highest TR-7A serial number I've
seen or heard about is serial number 12269.

Some of you may have seen the TR-7 transceiver cabinets in
black. Drake never built a TR-7 or TR-7A using a black cabinet. The Drake cabinets were
either the early version gray sometimes referred to as the "sticky paint" cabinet, or the later version
dark gray hard vinyl clad aluminum cabinet. So where did the black case come from? As I
understand the story, the black case was available from Drake after they stopped manufacturing amateur radio
equipment. After that time Drake was still receiving many
orders for replacement cases, so Drake had a quantity of them reproduced as replacement parts and sold them as
such for several years until they ceased providing spare parts and support
for all the Amateur Radio equipment.
But why a black case? During that time Drake's cabinet manufacturer
was producing black cases for other Drake products including the TR-270
and several of their short wave radios, so Drake decided to use the same
material because it was readily available.

The original
"sticky paint" case used a new type of paint that would resist scratches.
The only problem was after a while the paint started to break-down,
causing the surface to become tacky or sticky to the touch. As time
went on the cabinet paint started to deteriorate and discolored creating a
fairly ugly case. Fortunately, after producing around 2000 TR-7's
with this style case, Drake changed to the more popular textured dark gray
vinyl clad aluminum case.

Did Drake perform TR-7 to the TR-7A upgrades? Yes,
for a fee Drake did offer to upgrade the TR-7 to the later TR-7A version. What Drake did was to upgrade the
circuitry and internal wiring but did not change the outward appearance of the radio. Specifically,
Drake did not change the front panel top strip which shows the model
number.